Fault-indicating means for signal systems



Jan. 12, 1943. J. H. WHEELOCK FAULT INDICATING MEANS FOR SIGNAL, SYSTEMSOriginal Filed June 22, 1936 SQLEHCMD BM 2 W w 5 new 8 a z J u M w 14 wA wu u f 3 4 IL 3.9%. F 3d I :i L I p z 76 fi Ill a I a K M g I 9 U a Ja 1 J 2 o indicating signal.

Patented Jan. 12, 1943 FAULT-INDICATING MEANS FOR SIGNAL SYSTEMS John H.Wheelock, Fitzwilliam, N. H., assignor to Si nal Engineering &Manufacturing Company, New York, N. Y., a corporation of MassachusettsApplication February 28, 1940, Serial No. 321,323, which is a divisionof application Serial No. 86,512, filed June 22, 1936, now Patent No.

2,238,144, dated April 15, 1941.

Divided and this application April '7, 1941, Serial No. 387,126

4 Claims.

This application is a division of my copending application, Serial No.321,323, filed February 28, 1940, which copending application is adivision of my original application, Serial No. 86,512, filed June 22,1936, for an Alarm signal system, since issued as Patent No. 2,238,144,dated April 15, 1941, and relates particularly to improved means forindicating the occurrence of a fault, power failure, or any abnormalcircuit condition, which might occur in a system of the charactercontemplated by the aforesaid original application, or in any othersupervised electrical system.

In Wheelock Patent No. 2,170,104, issued August 22, 1939, there is shownand described an arrangement whereby fault-indicating means forsupervising an electrical circuit is also supervised, with provisionbeing made for concurrent supervision of the additional fault-indicatingmeans. A a result, any fault occurring in either the supervised circuit,or in the inter-connected circuits of the dual fault-indicating means,is immediately called to attention.

The invention of the present application relates to an improvedarrangement of the fault-indicatingm'eans and inter-connected circuitsdisclosed in my aforesaid Patent No. 2,170,104, whereby there isobtained additional supervision of certain parts of the electricalsignal system with which is associated.

fault-indicating signal directly in the supervisory circuit of thesystem under supervision, where it will of itself control actuation of asecond fault- Furthermore, provision is made for temporarily removingthe first signal from the main supervisory circuit, in order to cause itto indicate a fault in the other signal independently of the system, andtherefore without giving a false alarm.

The above and other advantageous features of -the invention willhereinafter more fully appear,

with reference to the accompanying drawing, in which:

Fig. 1 is a wiring diagram, illustrating a system i to which there hasbeen applied cross-supervision of the inter-connected fault-indicatingsignals, in

accordance with the present invention.

Fig. 2 is a schematic diagram based on Fig 1, illustrating functioningof one fault-indicating signal, upon the occurrence of a fault in thecircuit of the other signal.

Like reference characters refer to like parts in 1 the differentfigures.

The invention is shown in Fig. l, for purposes q o i) signal system, inwhich signals 1 are adapted to be sounded, or otherwise electricallyoperated, for giving an alarm. The signals l are shown as being of thesingle-stroke solenoid type with each providing an operating winding 2within which moves a magnetic striker 2a. The windings 2 of the signals1 are adapted to be connected in sections across the supply mains 3 and4, with balancing resistors 5 between the sections, by means of a numberof sets of relatively movable contacts 6 and l forming part of a mastercontroller, generally designated by the reference character A. Thecontroller A comprises a winding 8 and a magnetic armature 9 carryingthe contacts 6, with the contacts 6 and I being normally out ofengagement, as shown. 7

The winding 8 of the master controller A is shown as having one terminalthereof connected to the supply main 3 through a trouble signal circuit,hereinafter described, while the other terminal thereof is connected inseries with a number of alarm sending stations [0, disposed invariouslocations throughout the system. Each sending station provides asuitable contacting mechanism, here shown as comprising independentpairs of spaced stationary contacts ll, l2 and I3,

' l4, and in the normal, non-operating condition of the station, acircuit is maintained between contacts I l and I2 by a bridging member[5, while a second bridging member it maintains a circuit betweencontacts l3 and I4. The bridging members l5 and I6 are insulated fromeach other and in the operation of a station ID, are turnable in stationfarthest removed from the winding "8 in the circuit, is connected by astation conductor l8 to a controlling resistor It. The resistor I9 is inturn connected in series with. the signal windings 2 and balancingresistors 5, and the last signal winding 2 is connected to the fartheststation contact 13 through a station conductor 20. The circuit extendsthrough the bridged contacts I3 and I4 of the several stations, and aconductor 2| connects the nearest station contact M to the main 4through a current-limiting resistor 22. Normally, a small supervisorycurrent traverses the parts of the system described thus far, asfollows:

Beginning at the supply main G, the supervisory current flows throughthe resistor 22, bridged station contacts l4 and i3, and through thestation conductor 2% to the windings 2 and resistors 5 of the severalsections of signals. The current then passes through the controllingresistor l9 and station conductor iii to the other series of bridgedstation contacts i2 and ii, and from thence through the winding 8 of themaster controller A and the trouble signal circuit to the groundedsupply main 3. The value of this supervisory current is not sufficientto energize the winding 8, so that while the armature 9 remains down,the system remains in supervised condition; in readiness either for theoperation of the alarm signals, upon actuation of a sending station andbridging of contacts I! and M, or indication of a fault or any abnormalcircuit condition by a trouble signal, without operation of the alarmsignals, as will next be described.

The fault-indicating means of the present application contemplates atrouble signal 23 having a solenoid 24, within which operates a magneticplunger 25, adapted to strike a resonant member 26 in response to fullenergization of the solenoid 24. One terminal of the solenoid 24 isconnected to one side of a power source, such as a battery B, throughnormally closed interrupter contacts 21, operable when the plunger 25moves to its striking position. The other terminal of the solenoid 24 isconnected through a resistor 28 to the other side of sources B, withresistor 23 limiting the current flow through the solenoid 2% to such avalue as to maintain the plunger 25 slightly raised from its lowermostposition, just out of engagement with a flexible contact 29.

An auxiliary trouble signal 23' constructed in the same manner as thesignal 23, has one terminal of its solenoid 24' connected to thegrounded supply main 3, while its other terminal is connected throughclosed interrupter contacts 2'! to a stationary contact 30, normallyengaged with contact 29 of the primary trouble signal 23. .The contact29 is connected by a conductor 3! to the controller winding 8, so thatthe solenoid 2A is normally included in the main supervisory circuit ofthe system, including the stations ii] and signals I, all as previouslydescribed.

With supervisory current flowing through the solenoid 24' in series withother parts of the system, its plunger 25' is maintained slightly raisedfrom its lowermost position, just out of engagement with a pair ofnormally open contacts 32 connected across the terminals of the resistor28 that is in circuit with the solenoid 24 of the primary trouble signal23. Therefore, upon the occurrence of a break or ground in the system,or in the solenoid circuit of the signal 23', the resulting interruptionof supervisory current through the solenoid 24, causes the plunger 25'to drop to its lowermost position, and thereby close the contacts 32.This causes the resistor 28 to be short circuited, and fully energizesthe solenoid 24, whereupon the plunger 25 strikes the resonant member 26recurring strokes as long as the contacts 32 remain closed, due to theoperation of the interrupter contacts 21. The primary trouble signal 23will continue to indicate the existence of an abnormal circuit conditionin the system, until the cause of the trouble is remedied and the flowof supervisory current reestablished through solenoid 24', whereupon theplunger 25' will be partially raised from its lowermost position, topermit opening of contacts 32.

Referring now to Fig. 2, there is shown a schematic revision of thecircuit connections between the various pieces of electrical apparatusillustrated in Fig. 1. That is to say, the showings of the controller A,stations iii, and the trouble signals 23 and 23' have been simplified soas to give an across-the-line diagram, with the con- 7 tacts operated byfull current and supervisory current indicated by the proper legends.

If at any time there should occur a break or ground, where a groundedsource is used, in the circuit of the primary trouble signal 23, orshould the source 13 fail, the resulting deenergization of solenoid 24will permit the plunger 25 to fall to its lowermost position, as shownin Fig. 2. When this occurs, contact 29 is moved out of engagement withcontact 33, and into engagement with a stationary contact 33. Thus, theconductor 3| leading from the controller winding 8, is connecteddirectly to the grounded main 3, through contact 33 and a conductor 34,thereby maintaining the flow of supervisory current through the systemindependently of the solenoid 24' of the auxiliary trouble signal 23, asindicated by the open arrowheads in Fig.2 and holding the station andsignal circuits in operative condition to send an alarm. Movement of thecontact 29 to engage contact 33, is accompanied by movement of a contact35, mechanically connected to contact 29 by an insulating block 33. Thecontact 35 is connected to contactSil, and its movement by the plunger25 carries it into engagement with a stationary contact 37 connected tothe supply main 4 through a conductor 38 and the resistor 22, Closure ofthe contacts 35 and 3'! therefore connects the solenoid 24' directlyacross the supply mains 3 and 4, andthe resulting current flow shown bysolid arrowheads, causes operation of the auxiliary trouble signal 23'.This indicates either trouble in the circuit of the primary troublesignal 23', or failure of the source B, so that at all times, bothtrouble signals 22 and 23' are under constant supervision.

Should the armature 9 of the controller A be held up, due to the winding8'; remaining fully energized, a pair of normally open contacts 39, inparallel with contacts 32, will be closed by the armature 9. This willhavethe effect of shortcircuiting the resistor 28 to operate the primarytrouble signal 23 until the fault has been remedied and the armature 9returned to its normal down position, with contacts 39 open.

From the foregoing, it is apparent that by the present invention thereis provided an improved arrangement of a fault-indicating means forsignal systems, whereby a continuous supervision is obtained for thesystem, and the fault-indicating signals, as well as the connectionstherebetween. As a result, any fault occurring in either the supervisedsystem, or in the interconnected circuits of the dual indicating means,is immediately called to attention.

I claim:

1. In combination, an electrical circuit, including current responsivedevices and a first faultindicating signal, means for maintaining a flowof supervisory current through said circuit and signal, with the valueof said supervisory current insufiicient to cause operation of saiddevices or signal, a second fault-indicating signal, means formaintaining a flow 'of supervisory current through said second signalinsuii'icient to cause operation thereof, and means including crossconnections between said circuit and said signals, whereby anyinterruption of supervisory current through the first signal or circuitserves to operate the second signal, and any interruption of supervisorycurrent through said second signal serves to operate the first signal.

2. In combination, an electric circuit including current responsivedevices and a first fault-indicating signal, means for maintaining aflow of supervisory current throughsaid circuit and signal, with thevalue of said supervisory current insufiicient to cause operation ofsaid devices or signal, a second fault-indicating signal, means formaintaining a flow of supervisory current through said second signalinsufilcient to cause operation thereof, means including crossconnections between said circuit and signals, whereby any interruptionof supervisory current through the first signal or said circuit servesto operate the second signal, and means provided in said crossconnections, actuated in response to interruption of supervisory currentthrough said second signal, for operating the first signal independentlyof said circuit.

3. fIn combination, an electric circuit including current responsivedevices and a first fault-indicating signal, means for maintaining aflow of supervisory current through said circuit and signal, with thevalue of said supervisory current insuiiicient to cause operation ofsaid devices or signal, a second fault-indicating signal, means formaintaining a flow of supervisory current through said second signalinsuflicient to cause operation thereof, means including crossconnections between said circuit and signals, whereby any interruptionof supervisory current through the first signal or said circuit servesto operate the second signal, and means provided in said crossconnections, actuated in response to interruption of supervisory currentthrough said second signal, for removing the first signal from saidcircuit, in advance of operating the same, and for maintaining the flowof supervisory current through said circuit.

4. In combination, an electric circuit including current responsivedevices and a first faultindicating signal, means for maintaining a flowof supervisory current through said circuit and signal, with the valueof said supervisory current insumcient to cause operation of saiddevices or signal, a second fault-indicating signal, means formaintaining a flow of supervisory current through said second signalinsufiicient to cause operation thereof, means including crossconnections between said circuit and signals, whereby any interruptionof supervisory current through the first signal or said circuit servesto operate the second signal, and means provided insaid crossconnections, actuated in response to interruption of supervisory currentthrough said second signal, for removing the first signal from saidcircuit while maintaining the flow of supervisory current through saidcircuit, followed by operation of the first signal independently of saidcircuit.

JOHN H. WHEELOCK.

